The M4V file format is developed by Apple. It is similar to MP4. M4V files may be protected by Apple’s DRM copy protection. FairPlay prevents unauthorized reproduction of M4V files. Protected M4V files can be played only on authorized computers. Computers are authorized using iTunes. In QuickTime, protected M4V videos are marked as AVC0 Media.
M4V files use chapter information. M4V files handle AC3 audio. M4V files use the H.264 codec. The MP4 format can use H.264 or HEVC codec.
To play protected M4V files, authorize computer using account details. If file is not protected, change M4V extension to MP4. Install programs that support M4V files if files do not open. On Windows, open M4V files with iTunes or QuickTime Player. On macOS, open files with QuickTime Player. Convert M4V to MP4 to play files from unauthorized computer.
Apple iTunes
VLC Media Player
QuickTime Player